For fabrication of semiconductor devices, thin slices or wafers of semiconductor material require polishing by a process that applies an abrasive slurry to the wafer's surfaces. A similar polishing step is performed to planarize dielectric or metal films during subsequent device processing on the semiconductor wafer. After polishing, slurry residue is generally cleaned or scrubbed from the wafer surfaces via mechanical scrubbing devices.
It is known to provide an apparatus for cleaning a semiconductor wafer in which the wafer is submerged in a fluid, and megasonic energy is directed toward the wafer. However, it would be desirable to improve the cleaning of the edge of the wafer in such an apparatus.